Together with developments in science and technology, there have emerged many kinds of portable electric appliances for users' convenience in travels and business trips, such as laptop computers, mobile phones and portable fax machines and etc. Power adaptor is one of the many indispensable spare parts for these portable electric appliances in use and it is being developed in the direction of small size, easiness in carrying and safe applications. There are already many kinds of adaptors with foldaway plugs on the markets, which meet customers' demands to some extent, but they have the following disadvantages: the plugs are in contact with the power output terminals inside the adaptors through metal spring strip in only one point Poor contact will occur during long-time usage and the contact will become heated even burned in case of heavy load of power; the plug orientation has only two points for positioning that are easily worn in long-time usage and thus cause loss of orientation function or error In orientation.